When an insulated electrical conductor is wired into a circuit it is necessary to strip the insulation off the ends of the conductor. This is often presently accomplished by abrading the insulation with steel brushes. Because this abrasion produces copper and insulation dust, which may contain fiberglass, this method of stripping the ends of the conductors is considered t be a health hazard. Also, the resulting dust may contaminate the electrical apparatus being constructed, and there is a risk of injury from the rapidly rotating steel brushes.
Removing insulation by abrasion could be avoided if the insulation did not adhere to the conductor so that it could be easily cut away. It has been suggested to coat the conductor with various substances which will prevent the insulation from adhering to it. However, some of these substances, such as polytetrafluoroethylene, will not adhere to the insulation. Thus, if the insulation is not removed in a particular area where the polytetrafluoroethylene has been applied, the insulation will be weak in that area and may break off spontaneously and result in an electrical breakdown. Other substances, such as silicone, will contaminate the oils and other compounds which may be used in electrical apparatus.